A rolling mill vibration control method based on a machine learning analysis model

Abstract

The application provides a rolling mill vibration control method based on a machine analysis model, and belongs to the technical field of vibration control in a metal rolling process. The method comprises the following steps: determining an energy transmission path of a rolling mill vibration system, calculating energy values of each energy transmission path, calculating an energy value of vibration occurrence according to the energy values of each energy transmission path through an energy conservation law, taking the energy value of vibration occurrence as a boundary condition for solving a dynamic equation, and calculating a mechanism expression of vibration displacement; performing process analysis on the mechanism expression of vibration displacement to obtain rolling parameter adjustment strategies in different states; and performing rolling mill vibration control on the rolling mill vibration system by using the rolling parameter adjustment strategies in the different states. The control method improves the product quality of the strip steel and improves the production efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vibration control of metal rolling process, and particularly relates to a rolling mill vibration control method based on a machine analysis model. BACKGROUND

[0002] In the rolling process, the rolling mill vibration phenomenon directly causes the thickness fluctuation of the strip steel, and affects the product precision of the strip steel. When the vibration is serious, the strip steel and the roll may even be broken, causing economic losses and reducing the production efficiency. Through field research, it is found that the cold rolling vibration phenomenon often occurs in the last pass mill of continuous rolling, and occurs in the form of three times frequency vibration. The rolling mill vibration phenomenon has become a key factor restricting the improvement of product quality, and is a key problem urgently needed to be solved in the rolling field.

[0003] At present, the research on vibration depends on numerical simulation or data-driven methods. These methods only focus on analyzing the vibration under a specific working condition, lack the universal applicability of the model, and fail to establish a clear mathematical and physical relationship between the rolling process parameters and the vibration. In addition, they cannot obtain the displacement function expression of the vibration, so it is difficult to develop an effective vibration suppression strategy. This is the main reason why there is no better vibration suppression strategy research. Some researchers have also solved the equation by assuming boundary conditions, but the calculation results do not have physical meaning related to the rolling process, and cannot reflect the actual rolling process. At present, the main means of suppressing vibration on site is to reduce the rolling speed, which greatly reduces the production efficiency. Therefore, it is necessary to propose a vibration suppression rolling strategy for different working conditions. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a rolling mill vibration control method based on a machine analysis model. The control method of the application mainly aims to reveal the root cause of the rolling mill vibration and give a vibration suppression strategy under different working conditions.

[0005] The application provides a rolling mill vibration control method based on a machine analysis model, which comprises the following steps:

[0006] Determine the energy transmission path of the rolling mill vibration system, calculate the energy value of each energy transmission path, and calculate the energy value of the vibration occurring according to the energy value of each energy transmission path through the law of conservation of energy;

[0007] Take the energy value of the vibration occurring as the boundary condition for solving the dynamic equation, and calculate the mechanism expression of the vibration displacement;

[0008] Process analysis is performed on the mechanism expression of the vibration displacement to obtain a rolling parameter adjustment strategy under different states;

[0009] The rolling mill vibration system is controlled by the rolling parameter adjustment strategy under the different states.

[0010] The energy value of each energy transmission path is calculated, including:

[0011] The work done by the roll reduction is calculated;

[0012] The energy of the work roll rotation is calculated;

[0013] The work of the strip plastic deformation is calculated;

[0014] The friction heat generated in the rolling process is calculated.

[0015] The energy value of the vibration is calculated according to the energy value of each energy transmission path through the law of conservation of energy, including:

[0016] The energy value of the vibration is calculated according to the work done by the roll reduction, the energy of the work roll rotation, the work of the strip plastic deformation and the friction heat generated in the rolling process through the law of conservation of energy.

[0017] The energy value of the vibration is calculated according to the following formula:

[0018] W z =(W F +W J )-(W i +W f )

[0019] Wherein, W z is the energy value of the vibration, W F is the work done by the roll reduction, W J is the energy of the work roll rotation, W i is the work of the strip plastic deformation, and W f is the friction heat generated in the rolling process.

[0020] The mechanism expression of the vibration displacement is calculated by taking the energy value of the vibration as the boundary condition for solving the dynamic equation, including:

[0021] A mass-spring dynamic model is established for the upper work roll of the rolling mill vibration system, the intermediate roll is simplified as a point of concentrated mass, and the damping term between the intermediate roll and the work roll is ignored;

[0022] The mechanism expression of the vibration displacement is calculated by taking the energy value of the vibration as the boundary condition for solving the mass-spring dynamic model.

[0023] The mass-spring dynamic model is calculated according to the following formula:

[0024]

[0025] Wherein, Δf is the rolling force fluctuation value, M is the working roll mass, K is the inter-roller stiffness value, and y is the vibration displacement.

[0026] The vibration energy value is taken as a boundary condition for solving the mass-spring dynamic model to obtain a mechanism expression of the vibration displacement.

[0027] The mass-spring dynamic model is solved to obtain a solution result, and the calculation formula is as follows:

[0028]

[0029] Wherein, Δf is the rolling force fluctuation value, M is the working roll mass, K is the inter-roller stiffness value, y is the vibration displacement, C1 is the first coefficient, and C2 is the second coefficient.

[0030] The working roll vibration energy is calculated as follows:

[0031]

[0032] Wherein, W 振动 is the working roll vibration energy, W 势能 is the potential energy of the working roll, and W 动能 is the kinetic energy of the working roll.

[0033] Wherein,

[0034]

[0035] Wherein, v is the rolling speed.

[0036] The vibration energy value is taken as a boundary condition for solving the mass-spring dynamic model to obtain an equation, and the calculation formula is as follows:

[0037]

[0038] When the time when the rolling starts is equal to 0, the vibration amplitude at this time is c=0, the equation is solved to obtain the value of the first coefficient C1 and the value of the second coefficient C2, the value of the first coefficient C1 and the value of the second coefficient C2 are substituted into the calculation formula of the solution result to obtain a mechanism expression of the vibration displacement.

[0039] The mechanism expression of the vibration displacement is calculated as follows:

[0040]

[0041] Wherein, C1 is the first coefficient, C2 is the second coefficient, Δf is the rolling force fluctuation value, M is the working roll mass, K is the inter-roller stiffness value, t is the rolling time, h in is the strip inlet thickness, and hout is the exit thickness of the strip, V out is the exit speed of the strip, V in is the entry speed of the strip, h m is the entry thickness of the strip, W z is the energy of the vibration, which is calculated by the energy conversion formula.

[0042] The mechanism expression of the vibration displacement is analyzed to obtain the rolling parameter adjustment strategy in different states, including:

[0043] According to the mechanism expression of the vibration displacement, the influence of the change of the input parameter on the vibration displacement is analyzed.

[0044] According to the influence of the change of the input parameter on the vibration displacement and the mechanism expression of the vibration displacement, the vibration alleviation strategy in different rolling states is obtained.

[0045] According to the mechanism expression of the vibration displacement, the influence of the change of the input parameter on the vibration displacement is analyzed, including:

[0046] The change of the entry thickness of the strip is substituted into the mechanism expression of the vibration displacement to obtain the influence of the change of the entry thickness of the strip on the vibration displacement.

[0047] The reduction of the friction coefficient is substituted into the mechanism expression of the vibration displacement to obtain the influence of the reduction of the friction coefficient on the vibration displacement.

[0048] According to the influence of the change of the input parameter on the vibration displacement and the mechanism expression of the vibration displacement, the vibration alleviation strategy in different rolling states is obtained, including:

[0049] According to the influence of the reduction of the friction coefficient on the vibration displacement and the mechanism expression of the vibration displacement, the relationship between the friction coefficient and the vibration displacement is obtained, and the first strategy for alleviating the vibration is that, when the friction coefficient is continuously reduced, the rolling speed is increased to reduce the vibration displacement; the second strategy for alleviating the vibration is that, when the friction coefficient is continuously reduced, the rolling force is reduced or the inter-stand tension is increased to reduce the vibration displacement.

[0050] According to the influence of the change of the entry thickness of the strip on the vibration displacement and the mechanism expression of the vibration displacement, the relationship between the entry thickness of the strip and the rolling force and the inter-stand tension is obtained, and the first strategy for alleviating the vibration is that, when the entry thickness of the strip changes, the rolling force is adjusted by adjusting the reduction amount, and the inter-stand tension is adjusted.

[0051] Beneficial effects:

[0052] The application provides a rolling mill vibration control method based on a mechanism analysis model, discloses a mathematical and physical relationship between rolling mill vibration phenomena and rolling parameters, establishes a mechanism expression of vibration displacement, and based on the mechanism model, can analyze the causes of rolling mill vibration, can study control methods for inhibiting or reducing vibration under different working conditions, improves product quality of the strip steel, and improves production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 A rolling mill vibration control method based on a mechanism analysis model is provided for the embodiment of the application.

[0054] Figure 2 A rolling mill vibration system energy transmission path schematic diagram is provided for the embodiment of the application.

[0055] Figure 3 A work roll mass-spring model schematic diagram is provided for the embodiment of the application.

[0056] Figure 4 Influence of strip steel inlet thickness fluctuation on vibration displacement is provided for the embodiment of the application.

[0057] Figure 5 A friction coefficient change curve with rolling mileage is provided for the embodiment of the application.

[0058] Figure 6 A vibration displacement change curve with rolling mileage is provided for the embodiment of the application.

[0059] Figure 7 Influence of friction coefficient and rolling speed on vibration displacement is provided for the embodiment of the application.

[0060] Figure 8 Influence of tension stress before and after adjustment on vibration displacement is provided for the embodiment of the application.

[0061] Figure 9 Vibration displacement changes with rolling force and friction coefficient for the embodiment of the application.

[0062] Figure 10 Vibration displacement changes with rolling force and inlet thickness for the embodiment of the application.

[0063] Wherein, 1-rolling mill, 2-hydraulic press-down system, 3-motor drive system, 4-strip steel, 5-machine frame. DETAILED DESCRIPTION

[0064] The specific embodiments of the application are described in further detail below in combination with the drawings and examples. The following examples are used to illustrate the application, but are not used to limit the scope of the application.

[0065] Embodiment:

[0066] The application provides a rolling mill vibration control method based on a machine analysis model, as shown in the accompanying drawings, which comprises the following steps. Figure 1

[0067] Step S1: determining an energy transmission path of the rolling mill vibration system, calculating energy values of each energy transmission path, and calculating an energy value of vibration occurrence according to the energy values of each energy transmission path through the law of conservation of energy;

[0068] Step S2: taking the energy value of vibration occurrence as a boundary condition for solving a dynamic equation, and calculating a mechanism expression of vibration displacement;

[0069] Step S3: performing process analysis on the mechanism expression of vibration displacement to obtain rolling parameter adjustment strategies in different states;

[0070] Step S4: performing rolling mill vibration control on the rolling mill vibration system by using the rolling parameter adjustment strategies in the different states.

[0071] In the embodiment, first, the application discloses the root cause of vibration, which is excess energy in a dynamic system, from the perspective of energy conversion based on the law of conservation of energy in the rolling process. Then, the calculated excess energy is taken as a boundary condition to solve a dynamic equation of mass-spring, so that a mechanism expression of vibration displacement with mathematical and physical meanings is obtained. Finally, the derived mechanism expression is used to analyze the cause of vibration, and strategies for reducing vibration by adjusting rolling parameters such as rolling force, rolling speed and tensile stress are proposed for the cases of increased inlet thickness fluctuation and reduced friction coefficient, and the control effect of vibration is good.

[0072] In step S1, the dynamic system of the rolling mill vibration mainly comprises a roll 1, a hydraulic screwdown system 2, a motor transmission system 3, a strip steel 4 and a rack 5, and a dynamic system energy transmission schematic diagram is shown in the accompanying drawings. Figure 2 The input of the rolling mill vibration dynamic system is the screwdown of the hydraulic cylinder and the transmission of the motor transmission system 3: the hydraulic screwdown system 2 acts on the bearing seat on both sides of the support roll, transmits the rolling force to the work roll through the intermediate roll, and acts on the surface of the deformation zone of the strip steel 4, without considering the distribution of the rolling pressure along the width direction of the roll body; the motor transmission system 3 provides the torque required by the roll in the rolling process and drives the rotation of the work roll. The output of the rolling mill vibration system mainly includes the plastic deformation energy of the strip steel 4 when the strip steel 4 deforms, the friction heat generated between the work roll and the strip steel 4, and other energies such as the elastic deformation energy of the roll and the instantaneous temperature rise of the strip steel 4, which can be ignored due to being too small. When the input energy is too large and there is excess, vibration phenomenon occurs when the energy exceeds a certain energy threshold.

[0073] ​Step S1.1: Calculate the work done by the roll reduction. The energy of hydraulic pressure is the change of potential energy of the work roll in the vertical direction, which is equal to the work done by the rolling force P to reduce the thickness of the strip in the thickness direction. The present application assumes that the unit rolling pressure in the length direction of the roll body is equal, and the calculation formula of the work done by the rolling force reduction is as follows:

[0074]

[0075] wherein W F is the work done by the roll reduction, P is the rolling force in the deformation zone, and Δh is the reduction amount of the pass, i.e. the difference between the inlet thickness and the outlet thickness of the strip.

[0076] Step S1.2: Calculate the energy of the work roll rotation. The rolling mill is generally driven by the work roll, and the torque of the motor is transmitted to the work roll through the shaft coupling, speed reducer, etc., so the actual speed of the work roll is measurable. The energy of the work roll rotation is related to its own roll neck, mass and rotation speed, and the calculation process is as follows:

[0077]

[0078] wherein the moment of inertia J of the roll is:

[0079]

[0080] wherein W J is the energy of the work roll rotation, M is the mass of the roll, in kg; R is the radius of the roll, in mm; v r is the linear speed of the roll, in m / s; and t is the rolling time, and the research object in the present application is the unit rolling deformation zone.

[0081] Step S1.3: Calculate the plastic deformation work of the strip. There is a certain conversion relationship between the true strain in the length direction and the true strain in the thickness direction, so the plastic deformation energy of the strip can be expressed as follows:

[0082]

[0083] wherein W i is the plastic deformation work of the strip, V is the volume of the rolling deformation zone, in mm 3 ; is the average deformation resistance of the rolling deformation zone, in MPa; h in is the inlet thickness of the strip, in mm; and h out is the outlet thickness of the rolled strip, in mm.

[0084] Step S1.4: Calculate the friction heat generated in the rolling process. A large amount of friction heat is generated in the contact between the strip and the work roll, and the quality of the friction lubrication directly determines the stability of the rolling process. Friction force is generated at the rolling interface between the work roll and the strip, and the friction force can be decomposed into two components along the coordinate axis, i.e. the forward slip zone and the rear slip zone. The rear slip zone rolling force p back and the forward slip zone rolling force p front The calculation formula of the generated friction heat is as follows:

[0085]

[0086] Wherein:

[0087]

[0088]

[0089] Wherein, W f is the friction heat generated in the rolling process, l is the length of the deformation zone, and the unit is mm; l n is the neutral plane position; Δv is the difference between the exit speed and the entrance speed of the strip, and the unit is m / s; p back is the rear slip zone rolling force, p front is the forward slip zone rolling force, and the unit is N; μ is the friction coefficient; τ f is the friction force received by the strip deformation zone, and the unit is N; h in is the entrance thickness of the strip, and the unit is mm; h out is the exit thickness of the rolled strip, and the unit is mm; x is the position in the deformation zone, B is the width of the strip, and the unit is mm; h(x) is the thickness distribution curve of the strip deformation zone; h'(x) is the derivative of the thickness distribution curve.

[0090] Step S1.5: According to the work done by the roll reduction, the energy of the work roll rotation, the plastic deformation work of the strip and the friction heat generated in the rolling process, the energy value of the vibration is calculated by the law of conservation of energy.

[0091] In this embodiment, the roll and the strip are directly contacted through the deformation zone, and the study of the strip deformation zone can link the roll and the strip with the vibration system. Through the above calculation of various energy transmission in the vibration system, when the input energy is greater than the total output energy, there is excess energy in the system, and the vibration energy W z of the unit rolling deformation zone is calculated as follows:

[0092] W z = (W F + W J ) - (W i + W f) (8)

[0093] Since the setting of the cold continuous rolling schedule must meet the rolling capacity of each stand device, W z ≥ 0, that is, the input rolling force and rolling moment meet the rolling condition; according to the required strip thickness fluctuation range, the vibration energy threshold δ is set, when 0≤ W z ≤ δ, the rolling process is stable.

[0094] In step S2, the vibration energy value is taken as a boundary condition for solving the dynamic equation, and a mechanism expression of the vibration displacement is calculated,

[0095] In this embodiment, the vibration energy value obtained in step S1 is taken as a boundary condition for solving the dynamic equation, and a mechanism expression of the vibration displacement is calculated. The specific content includes:

[0096] Step S2.1: a mass-spring dynamic model of the upper work roll of the rolling mill vibration system is established, the intermediate roll is simplified as a point of concentrated mass, and the damping term between the intermediate roll and the work roll is ignored;

[0097] In this embodiment, the vibration of the rolling process directly affects the thickness accuracy of the strip, and the self-excitation vibration of the rolling mill is also directly generated by the contact area of the work roll and the strip, so studying the vibration of the work roll is better for suppressing and controlling the vibration. The mass-spring dynamic model of the upper work roll is established, the intermediate roll is simplified as a point of concentrated mass, and the damping term between the intermediate roll and the work roll is ignored, because once the vibration phenomenon occurs in the rolling process, only the artificial speed adjustment can reduce the vibration, and the vibration system cannot eliminate the vibration by itself. The mass-spring model of the work roll is shown in Figure 3 , K is the stiffness coefficient of the work roll, and M is the mass of the work roll. The displacement y of the work roll in the vertical direction is set, and the expression of the mass-spring model is as follows:

[0098]

[0099] Where Δf is the fluctuation value of the rolling force, unit: N; M is the mass of the work roll, unit: kg, K is the inter-roll stiffness value, unit: N / m.

[0100] The above differential equation is solved to obtain the calculation formula (10):

[0101]

[0102] Where C1 and C2 are two coefficients, and y is the vibration displacement.

[0103] Step S2.2: The vibrating energy value is taken as a boundary condition for solving the mass-spring dynamic model to calculate the mechanism expression of the vibration displacement.

[0104] In this embodiment, the mechanism expression of the vibration displacement is solved. Since the two coefficients C1 and C2 determine the amplitude of the vibration displacement, it is necessary to reasonably determine the coefficients C1 and C2. In this embodiment, the residual energy of the dynamic system obtained in step 1 is used as a boundary condition for solving. The energy of the work roll vibration can also be calculated by a physical equation, and the calculation formula is as follows:

[0105]

[0106] Wherein:

[0107]

[0108] The vibration energy calculated by the calculation formula (8) is the residual energy of the vibration system, which can only be released in the form of work roll vibration and maintain the stability of the dynamic system. Therefore, the vibration equation is combined with the actual production parameters by equating the energy calculated by the calculation formula (11). The calculation formula is as follows:

[0109]

[0110] When the start time is equal to 0, the vibration amplitude at this time is c=0, and the values of the two coefficients C1 and C2 are obtained by solving the equation, as shown in the calculation formula (14). Finally, the two coefficients are brought into the calculation formula (10) to obtain the vibration displacement function expression. The results show that the amplitude of the vibration displacement is related to the change of the rolling process parameters, the vibration frequency is related to the stiffness and mass of the work roll itself, and the vibration displacement equation has physical significance.

[0111]

[0112] Wherein, y is the vibration displacement, C1 is the first coefficient, C2 is the second coefficient, Δf is the fluctuation value of the rolling force, M is the mass of the work roll, K is the inter-roll stiffness value, t is the rolling time, h in is the strip inlet thickness, h out is the outlet thickness of the rolled strip, V out is the strip outlet speed, V in is the strip inlet speed, h m is the strip thickness before rolling, W z is the energy of the vibration, which is calculated by the energy conversion formula.

[0113] In step S3, the mechanism expression of the vibration displacement is analyzed to obtain the rolling parameter adjustment strategy in different states, including:

[0114] Step S3.1: According to the mechanism expression of the vibration displacement, the influence of the change of the input parameters on the vibration displacement is analyzed, including:

[0115] In this embodiment, based on the vibration displacement mechanism model established by the present application, the vibration causes are analyzed, and the influence of the change of the strip steel inlet thickness fluctuation, the friction coefficient reduction and other parameters on the vibration displacement is analyzed. The specific content includes:

[0116] Step S3.1.1: Substitute the change of the strip steel inlet thickness into the mechanism expression of the vibration displacement to obtain the influence of the change of the strip steel inlet thickness on the vibration displacement.

[0117] In this embodiment, the influence of the strip steel inlet thickness fluctuation on the vibration. The vibration displacement result of the strip steel inlet thickness fluctuation is as shown in Figure 4 Through the analysis of the actual data, it can be observed that in the stable rolling process, the thickness fluctuation is maintained within ±2μm. When the strip steel inlet thickness fluctuation increases to ±5μm, the vibration displacement amplitude increases from 0.24μm to 0.40μm, about 67%. When the inlet thickness fluctuation further increases to ±7μm, the vibration displacement amplitude increases to 0.56μm, about 133%.

[0118] From the perspective of energy conversion, this phenomenon can be explained as follows: when the inlet thickness increases, it effectively increases the reduction rate of the pass. If the rolling force is not adjusted accordingly, the energy input into the work roll by the system will increase, and at the same time, the plastic strain energy of the strip will also increase. However, at this time, the deformation resistance of the strip is reduced, and the change of the deformation energy is relatively small. This leads to the overall increase of the vibration energy of the dynamic system. The external excitation caused by the thickness fluctuation further amplifies the vibration, resulting in the gradual increase of the vibration displacement of the work roll.

[0119] Step S3.1.2: Substitute the reduction of the friction coefficient into the mechanism expression of the vibration displacement to obtain the influence of the reduction of the friction coefficient value on the vibration displacement.

[0120] In this embodiment, the influence of the reduction of the friction coefficient on the vibration displacement is obtained by substituting the friction coefficient function (15) into the vibration displacement function, and the friction coefficient curve changing with the rolling distance is as shown in Figure 5 The vibration displacement function is converted into a function containing the rolling distance parameter, and the result function shows the change of the work roll vibration displacement with the rolling distance, as shown in Figure 6 It is obvious that the continuous reduction of the friction coefficient during the rolling process leads to the gradual increase of the work roll vibration displacement.

[0121]

[0122] wherein μ0is a reference constant of the friction coefficient related to the lubrication state; μv is a reference constant for the influence of the rolling speed on the friction coefficient; v0is a reference value of the rolling speed in m / s; c R is a reference constant for the influence of the roughness of the roll surface on the friction coefficient; R a is the actual roughness of the work roll surface in pm; R a0 is a reference value of the roughness of the work roll surface in pm; c w is a reference constant for the influence of the accumulated strip length rolled by the work roll in a change of roll period on the friction coefficient; L is the accumulated strip length rolled by the work roll in a change of roll period in km; L0is a reference value of the accumulated strip length rolled by the work roll in a change of roll period in km.

[0123] This happens because as the roughness of the work roll surface decreases, the rolling force measured by the hydraulic system is greater than the force transmitted to the strip by the work roll. This results in excess energy being input into the work roll, and the remaining energy in the system increases. In order to maintain system stability, the work roll releases this excess energy in the form of vibrations, resulting in a gradual increase in the vibration displacement. When the friction coefficient decreases from 0.024 to 0.015, the vibration displacement amplitude increases from 0.18 pm to 0.71 pm, an increase of about 295%, indicating that the decrease in the friction coefficient has a significant impact on the vibration.

[0124] Step S3.2: According to the influence of changes in the input parameters on the vibration displacement and the mechanism expression of the vibration displacement, a vibration reduction strategy under different rolling conditions is obtained, including:

[0125] In this embodiment, based on the vibration displacement mechanism model established in this embodiment, the vibration control strategy is researched and analyzed, and a vibration reduction strategy under different rolling conditions is given.

[0126] Step S3.2.1: According to the influence of the decrease in the friction coefficient on the vibration displacement and the mechanism expression of the vibration displacement, the relationship between the friction coefficient and the vibration displacement is obtained, and the first strategy for reducing vibration is given: when the friction coefficient continuously decreases, the rolling speed is increased to achieve the purpose of reducing the vibration displacement; the second strategy for reducing vibration is: when the friction coefficient continuously decreases, strategies such as reducing the rolling force, increasing the inter-stand tension, etc. are used to achieve the purpose of reducing the vibration displacement;

[0127] In this embodiment, when the friction coefficient continuously decreases, the rolling speed is adjusted to achieve the purpose of reducing the vibration displacement.

[0128] Based on the established mechanism model, the relationship between the rolling speed and the friction coefficient on the vibration displacement is studied. The influence of the friction coefficient and the work roll rolling speed on the vibration displacement is as follows Figure 7The vibration displacement amplitude increased from 0.433 pm to 0.882 pm as the friction coefficient decreased from 0.025 to 0.015 when the work roll linear speed was 22 m / s during the constant speed rolling process. In this case, decreasing the rolling speed would continue to increase the vibration amplitude, but increasing the rolling linear speed would decrease the vibration displacement until it stabilized within an acceptable range.

[0129] When the friction coefficient decreased to 0.018, the vibration displacement amplitude decreased from 1.057 pm to 0.637 pm, a decrease of 39.7%, as the rolling speed increased from 19.0 m / s to 23.0 m / s. Similarly, when the friction coefficient was 0.025, the vibration displacement amplitude decreased from 0.921 pm to 0.208 pm, a decrease of 77.4%, as the rolling speed increased from 19.0 m / s to 23.0 m / s. It is clear from this analysis that the vibration displacement is significantly smaller when the friction coefficient is higher during the rolling process. With a decrease in the friction coefficient, increasing the rolling speed appropriately can effectively control the rolling mill vibration.

[0130] As the rolling distance increased, the friction coefficient decreased, and the vibration displacement showed an upward trend. In order to find a reasonable vibration reduction solution, Figure 8 The change in the work roll vibration displacement amplitude when the rolling distance was 50 km and the friction coefficient was 0.018 was illustrated by adjusting the front and back tension. When the back tension increased from 240 MPa to 330 MPa and the front tension increased from 210 MPa to 300 MPa, the work roll vibration displacement amplitude decreased from 0.71 pm to 0.65 pm, a total decrease of 8.5%. This is because when the friction coefficient decreases, the energy output of the system will decrease, resulting in an increase in excess energy. At this time, increasing the front and back tension will reduce the rolling force required to reach the same exit thickness and reduce the energy input of the system, thereby maintaining the balance between the input and output energy. However, adjusting the front and back tension alone is not enough to maintain the stability of the system.

[0131] Step S3.2.2: According to the influence of the change in the strip inlet thickness on the vibration displacement and the mechanism expression of the vibration displacement, the relationship between the strip inlet thickness and the rolling force and the inter-stand tension is obtained, and the first strategy to reduce vibration is given: when the change in the strip inlet thickness, the rolling force value is reduced by reducing the reduction amount, and the inter-stand tension is increased at the same time, to realize the stability of the rolling process.

[0132] When the abnormal fluctuation of the inlet thickness increases, the rolling force value is adjusted by adjusting the reduction amount, and the inter-stand tension is adjusted in coordination, to reduce the vibration displacement while ensuring the stability of the rolling process.

[0133] Under the rolling condition of continuously decreasing friction coefficient, in addition to adjusting the rolling speed, the rolling force can also be adjusted to reduce the vibration displacement amplitude. The results of the change of vibration displacement with rolling force and friction coefficient are shown in Figure 9 When the friction coefficient is reduced from 0.025 to 0.016, the vibration displacement continuously increases. During the reduction of the friction coefficient, the rolling force is adjusted from 7850 kN to 7700 kN, so that the vibration displacement amplitude of the work roll is reduced from the range of 0.46 μm to 0.78 μm to the range of 0.23 μm to 0.62 μm, the vibration displacement amplitude is reduced by 50% when the friction coefficient is high, and is reduced by only 20.5% when the friction coefficient is low. The result analysis shows that when the friction coefficient is too low, only adjusting the rolling force is not enough, other parameters must also be adjusted. In addition, when the friction coefficient is low, if the rolling force is too small, it is easy to cause the slip between the strip and the roll, which is also not conducive to the rolling stability.

[0134] When the strip inlet thickness increases, the effect of adjusting the rolling force on the vibration displacement is shown in Figure 10 When the inlet thickness fluctuation is increased from ±3 μm to ±7 μm, that is, when the strip inlet thickness is increased from 0.403 mm to 0.407 mm, the work roll performs too much work. By reducing the rolling force to reduce the energy input, the rolling force is reduced from 7850 kN to 7700 kN, resulting in a reduction of the vibration displacement amplitude from 0.598 μm to 0.451 μm, which is reduced by 24.7% compared with the value before adjustment.

[0135] Each of the embodiments in the present application is described in a progressive manner, and the same and similar parts between each of the embodiments can be referred to each other, and each of the embodiments mainly explains the difference from other embodiments.

[0136] The protection scope of the present application is not limited to the above-described embodiments, and obviously, those skilled in the art can make various modifications and changes to the present disclosure without departing from the scope and spirit of the present disclosure. If these modifications and changes belong to the scope of the claims of the present disclosure and the equivalent technology thereof, the present disclosure also intends to include these modifications and changes.

Claims

1. A method for controlling mill vibration based on a mechanistic analytical model, characterized in that, include: Determine the energy transmission path of the rolling mill vibration system, calculate the energy value of each energy transmission path, and calculate the energy value of the vibration based on the energy value of each energy transmission path using the law of conservation of energy. The energy value of the vibration is used as the boundary condition for solving the dynamic equation, and the mechanism expression of the vibration displacement is calculated. The mechanism expression of vibration displacement is analyzed to obtain rolling parameter adjustment strategies under different conditions; The mill vibration control is performed on the mill vibration system using the rolling parameter adjustment strategy under the different states described above. The calculation of the energy value of each energy transmission path includes: Calculate the work done by the roll pressing down; Calculate the energy of the work roller rotation; Calculate the work done by plastic deformation of the strip steel; Calculate the frictional heat generated during the rolling process; The mechanism expression for calculating the vibration displacement by using the energy value of the vibration as the boundary condition for solving the dynamic equation includes: A mass-spring dynamic model is established for the upper work roll of the rolling mill vibration system, the intermediate roll is simplified to a point with concentrated mass, and the damping term between the intermediate roll and the work roll is ignored; Using the energy value of the vibration as the boundary condition for solving the mass-spring dynamics model, the mechanism expression of the vibration displacement is calculated. The mass-spring dynamics model is calculated as follows: Where Δf is the fluctuation value of rolling force, M is the mass of the work roll, K is the inter-roll stiffness value, y is the vibration displacement, and t is the rolling time; The energy value of the vibration is used as the boundary condition for solving the mass-spring dynamics model, and the mechanism expression of the vibration displacement is calculated. The calculation process is as follows: The solution to the mass-spring dynamics model is as follows: Where Δf is the fluctuation value of rolling force, M is the mass of the work roll, K is the inter-roll stiffness value, y is the vibration displacement, C1 is the first coefficient, C2 is the second coefficient, and t is the rolling time. The energy of the work roll vibration is calculated using the following formula: Among them, W 振动 W is the energy of the working roll vibration. 势能 W is the potential energy of the working roll. 动能 The kinetic energy of the working roller; in, Where v is the speed of the roll; Using the energy value of the vibration as the boundary condition for solving the mass-spring dynamics model, the equation is obtained, and the calculation formula is as follows: When rolling begins, the rolling time t equals 0, and the vibration displacement y(0) = 0. Solving the equation yields the values ​​of the first coefficient C1 and the second coefficient C2. Substituting these values ​​into the calculation formula, the mechanism expression for the vibration displacement is obtained: Where y is the vibration displacement, C1 is the first coefficient, C2 is the second coefficient, Δf is the fluctuation value of the rolling force, M is the mass of the work roll, K is the inter-roll stiffness value, t is the rolling time, and h is the rolling time. in h represents the thickness of the strip at the entrance. out V represents the exit thickness of the rolled strip. out V is the strip exit speed. in h is the strip inlet velocity. m W represents the thickness of the strip before rolling. z It is the energy that causes vibration.

2. The mill vibration control method based on a mechanistic analysis model according to claim 1, characterized in that, The calculation of the energy value of the vibration based on the energy values ​​of each energy transmission path using the law of conservation of energy includes: The energy value of vibration is calculated by applying the law of conservation of energy based on the work done by the roll pressing down, the energy of the work roll rotation, the work of strip plastic deformation, and the frictional heat generated during the rolling process.

3. The mill vibration control method based on a mechanistic analysis model according to claim 1, characterized in that, The energy value of the vibration is calculated as follows: IN z =(W F +W J )-(IN i +W f ) Among them, W z W represents the energy value at which vibration occurs. F The work done by the roll pressing down, W J W is the energy for the rotation of the work roller. i For the plastic deformation work of strip steel, W f This refers to the frictional heat generated during the rolling process.

4. The mill vibration control method based on a mechanistic analysis model according to claim 1, characterized in that, The process analysis of the vibration displacement mechanism expression yields rolling parameter adjustment strategies under different states, including: Based on the mechanism expression of the vibration displacement, the influence of changes in input parameters on the vibration displacement is analyzed; Based on the influence of changes in input parameters on vibration displacement and the mechanism expression of vibration displacement, strategies for mitigating vibration under different rolling conditions are obtained.

5. The mill vibration control method based on a mechanistic analysis model according to claim 4, characterized in that, The step of analyzing the influence of changes in input parameters on vibration displacement based on the mechanism expression of the vibration displacement includes: Substituting the change in strip inlet thickness into the mechanism expression of the vibration displacement, the influence of the change in strip inlet thickness on the vibration displacement is obtained. Substituting the decrease in the friction coefficient into the mechanism expression for the vibration displacement, we obtain the effect of the decrease in the friction coefficient on the vibration displacement.

6. The mill vibration control method based on a mechanistic analysis model according to claim 4, characterized in that, Based on the influence of changes in input parameters on vibration displacement and the mechanism expression of vibration displacement, strategies for mitigating vibration under different rolling conditions are obtained, including: Based on the influence of the decrease in friction coefficient on vibration displacement and the mechanism expression of vibration displacement, the relationship between friction coefficient and vibration displacement is obtained. The first strategy to reduce vibration is: when the friction coefficient is continuously decreasing, increase the rolling speed to reduce vibration displacement. The second strategy to reduce vibration is: when the friction coefficient is continuously decreasing, reduce the rolling force or increase the tension between stands to reduce vibration displacement. Based on the influence of strip entry thickness on vibration displacement and the mechanism expression of vibration displacement, the relationship between strip entry thickness, rolling force, and inter-stand tension is obtained. The first strategy to reduce vibration is: when the strip entry thickness changes, the rolling force is reduced by decreasing the reduction amount, and the inter-stand tension is increased simultaneously to achieve the purpose of reducing vibration displacement.

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